Am I a madman

Am I mad, I hear myself think
and in the blink
of an eye
I am transformed into the most formidable wielder of a pencil this side of Bermondsey
although I have never been there
and wouldn't know how to find it with both my eyes shut.
Maybe I should just take the rest of my career off
and go and turn over vegetables in some hospital somewhere.
I am sure they could use the extra care and attention
although I have no intention
of wetting the beds in the middle of the night.